Tips for Growing Lilacs

Tips for Growing Lilacs

Lilacs are one of those plants that people either love or hate. Gardeners have been growing lilacs for centuries, not only because of the show-stopping spring blooms but also for the flowers’ exquisite fragrance. Folks who hate lilacs think of them as just a weed, but those of us who disagree with that opinion know that growing lilacs is a labor of love. Lilac-haters just misunderstand these lovely plants.

Whenever someone tells me that they hate lilacs, their reason for this disdain is because they think all lilacs send out suckers, causing the plants to spread out of bounds. While it’s true that the ordinary, common lilac, Syringa vulgaris, does sucker, there are over a thousand varieties of lilacs these days and many of those varieties do not sucker.

Non-suckering lilacs will quite happily continue to grow for many years right where they were originally planted, without threatening to overwhelm neighboring plants. The creation of all these lilac varieties serves as a testament to the popularity of growing lilacs.

Lilac varieties are quite diverse and range from small shrubs that reach only four to eight feet tall, on up to tree lilacs that can grow up to thirty feet tall. Most lilac varieties are hardy in Growing Zones 2 through 7, because lilac plants originated in the cool, lower mountains of Asia. But even those in warmer climates can be growing lilacs these days because there are a few varieties that will bloom in Growing Zones 8 and 9.

Warm-climate lilacs are mainly in the hyacinthiflora and oblate families and they are typically early bloomers, producing their flowers in the cool spring weather. In Zones 8 and 9, you can be growing lilacs called Anabel which produces pink flowers, or enjoying the fuchsia blooms of Pocahontas lilac, or the white flowers of Sierra Snow. In Zones 4-8 you might also look for the cut-leaf lilac, Syringa laciniata. This lilac generally grows up to 8 feet tall and blooms in late spring.

Other varieties that are suitable for growing lilacs in Zones 4-9 include Blue Skies which tolerates heat and humidity. Blue Skies produces highly fragrant lavender-blue blossoms.

Lavender Lady is a bit taller than Blue Skies and will bloom reliably in Zones 3-8, while Miss Kim is a bit shorter and is also a good selection for Zones 3-8.

Miss Kim is one of the more popular landscape lilacs these days. Also known as a Manchurian lilac, Miss Kim grows no more than nine feet tall and produces pink buds that open up to ice blue flowers in late spring. In the fall the foliage becomes an attractive dark red color. If you like growing lilacs but you have a small yard, the compact Miss Kim lilac would be a good choice.

Most folks enjoy growing lilacs for their beautiful flowers, but the plants bloom for only a couple weeks each year. To enjoy lilac blooms for even longer, plant several varieties with different bloom times. Charles Joly produces it’s deep purple double blooms fairly early in the season, while Chinese or Japanese tree lilacs bloom about two weeks later. One of my favorite lilacs, James MacFarlane, produces its flowery-scented pink blooms in early to mid-June.

James MacFarlane is a beautiful lilac variety with an unusual scent. This variety does not sucker and it’s a fast grower, quickly reaching its typical height of eight feet, and this lilac will often begin blooming the very next spring after it is planted. Swallowtail butterflies seem to be particularly attracted to James MacFarlane blossoms, another good reason for growing these lilacs.

While most lilacs bloom in shades of lavender, pink or white, there are also yellow-blooming cultivars available now. Primrose is a yellow lilac that is hardy in Zones 3-7. For a real standout in your garden, add a yellow Primrose lilac to your collection.

Growing lilacs doesn’t come without a few pitfalls, and the most common problem is powdery mildew. Powdery mildew often occurs in hot, humid weather and it causes the leaves to develop a dusty white coating. Powdery mildew is unsightly but it rarely causes serious harm to lilacs.

The foliage can be sprayed with a fungicide two or three times a week to treat powdery mildew, or it can be prevented with a spray of potassium bicarbonate which can often be found at garden centers. Some varieties of lilacs are more resistant to powdery mildew than others, so if humidity is a problem in your area, consider growing lilacs that are powdery mildew-resistant, such as Miss Kim or James MacFarlane.

If a lilac bush isn’t blooming up to par, or not blooming at all, there are several possible reasons for the lack of blooms. It could be that the plant is not yet mature enough to bloom. Most varieties will not begin to bloom until after they have been planted for three or even four years. If you’re newly-planted lilac hasn’t bloomed yet, just give it some time to grow up and establish itself. A lilac that has been transplanted will often take a break for a year also before it resumes blooming.

Make sure your lilacs are growing in full sun. Lilacs bloom best in full sun and may not bloom well if they’re being shaded by taller plants.

If a lilac needs pruning, this should be done immediately after the plant has finished blooming for the season. Lilacs form new buds soon after the flowers die back, so if the plant is pruned later in the summer, over winter or in the early spring, those flower buds will be pruned off and there will be no flower show the following spring.

If high-nitrogen fertilizer is applied to a lilac or to the lawn near a lilac bush, the nitrogen will cause the lilac to spend all of its energy on growing more foliage at the expense of blossoms. Nitrogen fertilizer promotes foliage growth but can prevent the plant from making flowers. Use a fertilizer higher in phosphorus to promote flowering, but lilacs are generally quite vigorous and rarely need fertilization.

Growing lilacs is really quite easy, and by choosing the best variety for your yard, even the most ardent lilac haters can learn to love lilacs.

Comments

I have tried to root cuttings from my lilac several times, with no success. This lilac was started from my grandmother’s huge plant. We put it in a spot where it isn’t happy, and I have a better place in mind.
Just today I started again. I took cuttings from the tips, leaving 2-4 leaves, with 2-3 nodes on each cutting. Rooting hormone powder on the nodes, then I put them in cups full of moistened seed starting mix. (Peat moss, vermiculite, perlite and wetting agent.) My thought was that I could leave that soilless mix in place when I replant my new, free lilacs into larger pots. (I want to grow them big enough before planting them in the yard that my husband won’t mow them down.)
Then I found your site. You say they should be in sand, and that I should keep them covered in plastic.
Should I pull my cuttings, dump the starting mix and go steal sand from my neighbor’s kids’ sandbox and replant my cuttings? Should I take new cuttings for the new cups of sand? Should I keep them inside or outside? Is it too late for success this year? (Late June, west central Ohio)
A gardener friend thinks I have left too many leaves. How many should be left?
Thanks for any advice. This plant means a lot to me!

I live in Georgia. My Miss Kim lilac is blooming but looks leggy (no leaves on lower sections of stems). The leaves are spare towards the top….but it is blooming! It gets full sun, plenty of circulation. Any advice on how to help the poor thing? It looks sad….and I want a happy lilac!

mike, is there any hope for pruning a mature lilac that has never been pruned correctly (if at all) ? it has had very few blooms towards the top since we moved here three summers ago, and i’d like to know if it can be pruned to produce more.

i’ve also read in the past that you can dig out suckers to replant if you follow the roots into the parent plant, needing to take part of the parents root inorder for it to grow. this was well over ten years ago that i came across this information. i don’t know if it’s right or not.

Yes, you can prune an old lilac to give it new vigor again. The best time to do that is right now while the plant is still dormant. Cut it as low as you’d like. Keep in mind, there is a slight risk of harming the plant, but it is very slight and you have ask yourself; Is this plant adding or detracting to my yard as is. You can dig out suckers and replant them and no you don’t have to go any point on the parent plant, you just have to get enough roots to support the piece you are transplanting. Do that now while dormant. Yes you can root cuttings in June, see this http://mikesbackyardnursery.com/2015/01/easy-summertime-plant-propagation-techniques-can-home/

Mike my little dappled willow is in trouble. Several branches just dried up, and now I notice a blotchy light peach color scale on the trunk. can you tell me what I can do or if this is a bad problem. I have had it for two years now and it was fine until this Spring. Thanks Judy

I’m not familiar with a scale that attacks dappled willow, but that doesn’t mean that there is one. You can spray, but getting rid of scale is not easy because the actual insects that live under the scale bunkers only move once or twice a year where you can actually get them with spray. Try something systemic and see if that works. But I’d consider replacing the plant. Often the chemical controls can cost more than a new plant.

I planted a lilac several years ago near the front corner of my house, outside the window of the “computer” room. I thought it would be wonderful to open the window and smell the lilacs. Well, the poor little old thing (5 or 6 years old) doesn’t bloom very well and I’m thinking it doesn’t get enough sun. When can I transplant this poor shrub? By the way, I’m using my “clam-shell propagator” on a dark purple lilac in the back yard, wish me luck.

i have a stand of lilacs that have been in 20 years.. The blooms always get frozen here in mid southern Utah. Have the same problem trying to grow fruit. Can you suggest late blooming varieties for zone 4 that might avoid this problem?

Any wisdom regarding the reblooming lilacs, such as Josee Lilac? What are its maintenance and its pitfalls?

A nursery states, “A Dwarf Lilac That Blooms Until Frost! This hardy lilac loves the sun and is just the right size (at 4-6 ft. tall) as an accent shrub or grouped as a hedgerow. Fragrant, lavender-pink panicles of trumpet-shaped flowers are 4-5 in. long and can’t be beat as cut flowers. Even butterflies can’t resist this lilac.” Thank you.

My lilac bush originally came from my Grandmother’s farm. As a child I remember the scent – a strong sweet smell wafting across acres of fields. That was over 60 years ago & I think of her every spring my lilac is in bloom.

Mike,
Thanks for sharing….much appreciated.
My comment/question is the picture above of the “Syringa Vulgaris” TREE. How does one prune this to have the same results? I will be moving to Ontario, Canada soon and would love to plant many lilacs in the tree forms rather than a bush.